Volume 7, No. 4 (2006)
Articles
INFLUENCE DE CERTAINES SOURCES DE NUTRIMENTS ET DE FACTEURS DE CROISSANCE SUR LA VIABILITE DES BIFIDOBACTERIES
BARASCU ELENA
In this paper, the influence of the yeast extract and wheat germs on viability of bifidobacteria in fermented milk in 19 days at 3-4 °C has been studied, in order to use the results in the technology of probiotic dairy products. The survival of bifidobacteria was better in fermented milk with yeast extract and wheat germs than in fermented milk without these ingredients, the population of bifidobacteria remaining higher than 109 cfu/cm3 in those m19 days of the experiment. Consequently, the yeast extract and the wheat germs have improved both the growth rate of bifidobacteria, the populations of bifidobacteria from the fermented milk being higher than 109 cfu/cm3 and the rate of survival of bifidobacteria in fermented milk. Furthermore, the yeast extract and wheat germs have contributed to the improvement of the nsensory attributes of the fermented milk with bifidobacteria, offering to the product a very pleasant cream color and an interesting taste of cake with nfermented milk.
EFFET DE L’EXTRAIT DE LEVURE SUR LA CROISSANCE ET LA VIABILITE DES BIFIDOBACTÉRIES
BARASCU ELENA
The study concerned on the influence of the yeast extract on the growth of bifidobacteria in milk and, also, the improvement of viability of those bacteria in fermented milk with this ingredient, in order to use the results in the technology of probiotic dairy products. The growth of bifidobacteria was better in milk with yeast extract, because the growth rate of bacteria was 4 times higher and the generation time was 4.5 times lower than in simple milk (without ingredient). In conclusion, through the supplementation of milk with yeast extract were managed both the increase of the multiplication of bifidobacteria in milk, and the improvement of viability of those bacteria in fermented milk. Also, the yeast extract has contributed to the improvement of the sensory attributes of the fermented milk only with bifidobacteria, offering to the product a very pleasant cream colors and an interesting taste of cake with fermented milk.
ESTIMATION OF VITAMIN C AND Cd, Cu, Pb CONTENT IN HONEY AND PROPOLIS
DOBRINAS SIMONA*, MATEI NICOLETA, SOCEANU ALINA, BIRGHILA SEMAGHIUL, POPESCU VIORICA
The bee colony collect for their own developmental needs the nectar, honeydew, resinous substances (to produce propolis), pollen and water from the environment that unfortunately is often exposed to various contaminants that can be found in the human consumed foods. Vitamin C and three heavy metals (Cd, Cu and Pb) were determined in honey samples produced from different plants (sun flower, conifers, multifloral, mountain flowers, pine tree forest, acacia and linden tree) from 14 regions of Romania (Babadag, Bragadiru, Brezoi, Calafat, Câmpulung, Constanta, Dâmbovita, Dragasani, Deva, Pecineaga, Peris, Podisul Transilvaniei, Timis, Râmnicu Vâlcea) and in propolis produced from Timis region and in two commercial samples. The investigated samples were collected from beekeepers and local market during 2002 - 2004. Vitamin C content was analyzed using a titrimteric method with potassium bromate-bromide solution in acidic medium and the heavy metals were determined in bee products by flame atomic absorption spectrometry (FAAS) and inductively coupled plasma atomic emission spectrometry (ICP-AES) and the results were compared. The results of the FAAS analysis are in good agreement with those given by ICP-AES.
LA STABILITE PHYSICO-CHIMIQUE D’ESTURGEON DU DANUBE (ACIPENSER STELLATUS) A CONGELATION
IONESCU AURELIA(1)*ANDZARA MARGARETA(1), APRODU IULIANA(1), VASILE AIDA(1), PALTENEA ELPIDA(2)
The sturgeon (Acipenser stellatus) is the third important species of sturgeons for the production of caviar and firm, tasty white, meat fresh or refrigerated. Freezing, as fish conservation technology, involves biochemical modifications that dictate the fish quality in terms of texture, nutritional value and security.
MONITORING DES NITRITES ET NITRATES RESIDUELS DES PRODUITS DE VIANDE SALEE AVEC LE TESTE NITRITE MERCKOQUANT
IONESCU AURELIA(1)*ANDZARA MARGARETA(1), APRODU IULIANA(1), VASILE AIDA(2), CARAC GETA(3)
The present work is an analytical study concerning the level of residual nitrites and nitrates in various salted meat products manufactured in Romania. The complexity of the food matrix, the extracting conditions of the food additives, the reduction method of nitrates to nitrites, and the quantification method of free and total nitrites became the main factors that conditioned the obtained values for these parameters, important for defining the chemical hazard of the up mentioned products. The alkaline method gave a better extraction of nitrites and nitrates comparatively to the reference method; the manual reduction applied to a single sample assured a better conversion yield than the method involving column reduction on a cadmium-zinc sponge; the photometric method with nitrite-test for residual nitrites and nitrates quantification gave slightly lower values than the Greiss reference standard method.
ETUDE DES TRANSFORMATIONS CHIMIQUES ET HISTOLOGIQUES PENDANT LA CONGELATION ET LE STOCKAGE DE LA VIANDE
MANEA IULIANA(1), BURULEANU LAVINIA(2), MANEA LAUR CONSTANTIN(3)
The aim of this paper is the study of the transformations that take place during freezing and stocking of the meat in order of applying the most adequate freezing method for maintaining meat’s quality at the highest level.
RECHERCHES CONCERNANT L’EVOLUTION DU CONTENU DE LA VITAMINE C DANS LA TAMARIX RAMOSISSIMA ET LE JUS TAMARIX RAMOSISSIMA
MANEA IULIANA(1), MANEA LAUR CONSTANTIN(2)
The aim of this work is the study of the evolution of vitamin C content in saltcedar (Tamarix ramosissima) and in saltcedar juice preserved in different ways: freezed, refrigerated, pasteurized, sweetened with sugar, sweetened with sugar and refrigerated.
REPONSE ELECTROCHIMIQUE DE L’ALUMINIUM EN CONTACT AVEC LA BIERE
MARECI DANIEL(1), POPA IONEL MARCEL(1), UNGUREANU GINA*(1), AELENEI DELIA(1), MIRZA ROSCA JULIA CLAUDIA(2)
The aluminum, a very oxidable material from the thermodynamically viewpoint, has an excellent corrosion resistance, due to the thin and adherent oxide layer formed onto its surface. By using electrochemical methods – potentiometry and EIS – the electrochemical parameters of the corrosion process of aluminum in beer have been determined: the corrosion potential (Ecorr), the corrosion intensity (Icorr), the polarization resistance (Rp), the pitting potential (Egp) and the repassivation potential (Erp). The equivalent circuit used is typically for pitting corrosion. Optical microscopy has been used for completing the analysis of attacked surfaces. The experiments showed the localized corrosion susceptibility of aluminum in contact with beer.
PHYSICO-CHEMICAL AND ANALYTICAL CHARACTERIZATION OF SOME EXTRACTS, MACERATES AND FRESH FRUITS FROM ROSACEAE FAMILY
POPESCU VIORICA(1), SOCEANU ALINA*(1), DOBRINAS SIMONA(1), BIRGHILA SEMAGHIUL(1), MAGEARU VASILE(2)
The aim of this work was to study the content of Fe, Mn, Zn and Cu in the mixtures which contain volatile oils among other components, obtained after the Soxhlet extraction, maceration or ultrasonic technique of the samples and in the fresh fruits (Malus domestica and Cydonia oblonga). Both fruits belong to the same family named Rosaceae. subfamily Maloideae (or Pomoideae) whose fruits consist of five capsules (called "cores") in a fleshy endocarp, surrounded by the ripened stem tissue. Flame atomic absorption spectrometry (FAAS) was used for the quantitative determination of metals in these matrixes and fruits (dry weight). Also, the refraction indices and conductivity were measured using Abbe refractometer and LF 340-A conductometer, for the characterization of the obtained mixtures, respectively for correlation with the mineral content. It was observed that iron concentrations are in higher quantities than Mn, Zn and Cu in both studied fruits.
ANALYSE QUALITATIVE ET QUANTITATIVE DES ANTHOCYANES DANS DES PRODUITS NATURELS
SAVA CONSTANŢA(1), SIRBU RODICA(2), DUMITRESCU CRISTINA(3)
The objective of the research was the extraction of anthocyanes from natural products using several specific solvents. The study was necessary due to the fact that many works reported the benefit effect of these antioxidant compounds on the human health. Much more, there is a growing interest for replacing synthetic colorants with natural pigments, the anthocyanes being second to none, due to their live and various colors, combined with their protective effect.
DETERMINATION QUANTITATIVE DES ANTHOCYANES POUR LEUR UTILISATION DANS L’INDUSTRIE ALIMENTAIRE ET PHARMACEUTIQUE
STANCIU GABRIELA(1), MIHAIESI MIRELA(2), LUPSOR SIMONA(1)
The work presents the study over several types of wines as: Cabernet Sauvignon, Merlot, Pinot noir, Burgund and Blauerzweigelt through out a period of three years. Also in this paper are presented the results of quantitative determination of anthocyanins from five kinds of black grapes containing important quantities of anthocyanins in fresh condition as well as grape spirits – sub product of the wine preparation process and as well the dynamics of anthocyanins accumulation during maturation in order to establish the optimum moment to reap the grapes for wine preparation process as well as to utilize the grape spirits as a source of anthocyanins for the food industry and pharmacy. The determinations were carried out using a UV-VIS CAMSPEC 330 Spectrometer.
RHEOLOGICAL ANALYSIS OF SOME PHARMACEUTICAL GELS CONTAINING TINCTURE OF PROPOLIS
STANCIU GABRIELA(1), MITITELU MAGDALENA(2)
In the rheological study of pharmaceutical gels the rheological properties evaluation at different experimental parameters play an important role for their quality control and also for the optimization of their formulation. In this work, four gels with carbopol 940 1% and tincture of propolis in different concentrations: 1, 3, 5, and 7%, have been prepared. The rheological profiles of the gels t = f(?, Dr) and their spreadability has been analyzed.
APPLICATION DU POUVOIR TAMPON POUR L’ACIDIFICATION OU LA DESACIDIFICATION DES VINS
TITA OVIDIU(1), TITA MIHAELA(1), DABIJA ADRIANA(2), SION IULIANA(2)
The buffering acidic-basic capacity gives the wines a good physical, chemical, microbiological and sensorial stability. In the case of the white wines it may cause a biological deacidification, the wine becoming still and thus the chemical reacidification of the wine using citric and tartaric acid is necessary. Due to their composition, the musts and wines are acidobasic buffer solutions and it can be stated that a change in the physical and chemical content generates a limited variation of the pH value, thus explaining the relatively minor variations of the must’s pH during the acidobasic and malolactique fermentation the buffer power can be mathematically formulated, this parameter’s quantification being necessary.
APPLICATIONS DE LA REFRIGERATION DES VINS DANS L’ASSURANCE DE LA STABILITE TARTRIQUE
TITA OVIDIU(1), TITA MIHAELA(1), DABIJA ADRIANA(2), SION IULIANA(2)
The excess of tartaric salts determines in certain conditions the formation of characteristic crystals that fall in the form of sediment. The crystallization and sedimentation of the tartaric salts are useful when they take place in the sedimentation vessel and are an inconvenience, especially from a commercial and sensorial point of view, when they appear in the bottled wines. The formation of a small crystal, called the nucleus in the liquid stage, corresponds to the creation of an interface between the two phases, process that requires a lot of energy, called interfacial energy. In the wine, the phenomenon is influenced by the presence of macromolecules inhibited by the phenomenon of agglomeration of the tartaric salts.
ANALYSE BIOCHIMIQUE DE L’AIR RESPIRÉ
CIOBANU OCTAVIAN(1), CIOBANU GABRIELA(2), SANDU ION(3)
A conductometric method implying some devices was applied in order to perform some biochemical analysis on expired breath; experimental data were compared with data furnished by a laser type particle counter. Results obtained by this method and devices, developed for „in situ” determination of NaCl aerosol concentration of therapeutic environments, showed a good sensibility. Measurements permit determination of efficacy of an aerosol therapy.
SOLUBILITE EN MELANGES SOLVANT –ANTISOLVANT. UNE ETUDE CALORIMETRIQUE DES DIAGRAMMES DE PHASES SOLIDE-LIQUIDE EN SYSTEMES TERNAIRES
HAMEDI MOHAMED H.(1), GROLIER JEAN-PIERRE E.(2)*
In crystallization engineering, a crystallized powder of a pure component can be obtained in a selected solvent-antisolvent system. It has been proposed that binary water-alcohol mixed solvents can be used for this process. Isothermal titration calorimetry has been used to construct the solid-liquid equilibrium line in ternary systems containing the solute to precipitate and an aqueous-alcohol mixed solvent. Phase diagrams have been established over the whole concentration range for some benzene substituted derivatives, including o-anisaldehyde, 1,3,5-trimethoxybenzene and vanillin, in {water + alcohol} mixtures at different temperatures.
LES PROPRIETES REDOX DE VIOLOGENS SYMETRIQUES
IRIMIA MARINELA(1), AVRAM ECATERINA(2), AELENEI NECULAI(3)
The symmetric viologenes are bi-quaternary salts of 4,4’- bipyridil which may be obtained through nucleofile substitution (SN2) at nitrogen atoms with reactive halogenated derivates, such as a-halogenoesters and a-halogeno-ketones. It is known that the viologenes present three oxidation states: Viologen+2, Viologen+ and Viologen0, each of them having a certain color, and specific magnetic, electrical, vibrational and spectral properties. The bipyridinium cation (Viologen2+) is a stable state that may be transformed into Viologen+ or Viologen0 through a redox reactions activated by visible radiation. These redox processes could be reversible or not, depending on the nature of the viologen, of the electrolytic support, of the solvent and of the operating conditions. The complexity of these transformations may be clearly evidenced through cyclic voltammetry (CV). Our studies have been performed in 0.1M KCl aqueous solutions, with glassy carbon electrode. We have concluded that the CV signals given by viologenes synthesized starting from a-halogéno-esters are the most important. We can affirm that the electrochemical processes corresponding to these types of viologenes take place at a higher rate than other viologenes. The study of the redox properties allowed us to explain the behavior of different viologenes under irradiation. The viologenes have been introduced in a poly (vinylic alcohol) matrix, and the electronic absorption spectra modifications under UV radiations have been recorded. The specific behavior of each type of viologen has been studied.
MODELE DE PROPRIETES THERMODYNAMIQUES DE SOLUTIONS AQUEUSES ELECTROLYTIQUES
BEN GAÏDA L.*, GROS J.-B., DUSSAP C. G.
A new chemical-physical group contribution model for activity coefficient is proposed to estimate the equilibrium properties of aqueous solutions containing electrolytes. The chemical part of the model accounts for the hydration equilibrium of water and ions with the formation of ions n-water complexes in a single stage process; n, the hydration number, and K, the hydration equilibrium constant, are the two independent parameters in this part. The physical part of the model is the UNIFAC group-contribution model for short range interactions. Each ion is considered as a group. Long range interactions are accounted for by a Pitzer (Debye and Hückel theory) contribution. The model is compared to experimental data including water activity, osmotic coefficients, activity coefficients, and pH etc. of binary concentrated electrolyte solutions (20M NaOH, 16M HCl, etc.).
ADSORPTION COMPETITIVE DE SURFACTANTS ET DE BLEU DE METHYLENE A L’INTERFACE COTON / EAU
MOATER ELENA IRINA*, RADULESCU CRISTIANA, IONIŢĂ IONICĂ, HOSSU ANA-MARIA
The adsorption study of surfactant-dye aqueous solutions on the cellulosic materials is very important, knowing that the mixed surfactant-dye micelle can reach in the surface waters, while through adsorption the surfactants can be accumulate in soil and they can influence the normal development of the plants and live organisms. It has been studied the competitive adsorption between: biodegradable nonionic surfactants, cationic surfactants with antiseptic properties, germicides and the methylene blue, a vital dye on cotton/water interface. By UV-VIS spectrophotometric and tensiometric measurements it was determinate the form of adsorption isotherms on cotton for methylene bluemicellar surfactant aqueous solutions. The classic quantitative methods (Langmuir, Fowler-Guggenheim) that describe the surfactant adsorption on solid/liquid interface have been tested, allowing the description of the interaction type and the accumulation mode of mixed surfactant-dye micelles on cotton/water interface.
INHIBITION DE LA CORROSION DE L’ACIER DANS LES EAUX DE GISEMENT
MORARU M.(1), SCHIOPESCU AL.(1), ROSU DORIN(2), STEFANESCU E.(2), CAMENITA I.(1)*, AVRAM LAZAR(1)
Corrosion of steel in the oil-field waters has many aspects. It is known that metals corrosion is due to the dissolution of metal accomplished by the reduction of one of environment’s components. The laboratory studies required to know the chemical composition of the corrosive aqueous environment and the metal – environment interactions. Corrosion rate has been determined through the weight loss of corrosion coupons and has been expressed as gravimetric index. The effect of Na-lignosulphonate on the corrosion rate of steel in deposit waters has also been studied.
«TABOU SEARCH» METHODE DANS LA GENERATION ASSISTEE SUR ORDINATEUR DES COMPOSES MACROMOLECULAIRES
RUSU TEODORA(1), GOGAN OANA MARLENA(2)
The Tabou method is a strong heuristic method giving very good results for monocriterial problems. The numerical results obtained in multiobjective problems are presented, and Tabou method is compared with other known methods (genetic algorithms). The genetic algorithms are already used in the computerized optimization analysis of the macromolecular products synthesis. The generation of the initial population may be done by random creation of a fixed number of chromosomes, imposing the condition that each chromosome is a valid solution of the desired macromolecular structure. The evaluation of a population is done by assigning to each individual an evaluation function. The work presents an experimental study of using mixed genetic – Tabou algorithms applied in a multicriteria context.
RECHERCHES SUR LA NATURE ET LA LUTTE CONTRE LES DEPOTS MICROBIOLOGIQUES DANS LES CIRCUITS D’EAU D’UNE MACHINE A PAPIER
STANCIU CONSTANTIN
The micro-organisms are giving various problems in the paper manufacturing processes: holes in the sheet of paper caused by slime, the contamination of the additives, odors and corrosion. These microorganisms have the tendency to make agglomerations and to fix themselves on the walls of the circuits of paper machines like bio-films. The capacity to fix itself on the walls of the water circuits is a characteristic of micro organizations. In the first part of the paper the conditions of development (nutrients, water, free and combined oxygen, and temperature) are presented and contamination sources with the main microbial populations are identified. The main biological components of the deposits in a paper factory are the bacteria, the yeasts and the moulds. A comparative situation of the bacterial charge of three different water circuits (paper made from 100% bleached pulp, paper made from 100% virgin pulp, and paper made from 100% deinked pulp is presented. The most contaminated circuits are those involved in processing old papers. It was also studied the microbiological loading at a certain time of the year (the most serious problems appear during spring – autumn) and also according to the kind of paper manufactured (especially acid or alkaline). The negative effects of the proliferation of the bacteria can be drawn aside by the specific use of biocides. The efficiency of the use of a biocide depends on pH, dosing place, the added amount and also the mode of dosage (shock or continuously).
SYNTHESE CASCADE EN MILIEU BASIQUE DE LACTONES. APPLICATION A LA SYNTHESE DE LA CERPEGINE ET D'ISOBENZOFURANONES
VILLEMIN DIDIER(1), LIANG LIAO(1), BAR NATHALIE(1), CHEIKH NAWEL(2), MOSTEFA-KARA BACHIR(2), CHOUKCHOU-BRAHAM NOUREDDINE(2), DIDI MOHAMED A.(2)
New cascade synthesis (domino synthesis) of butenolides starting from alpha hydroxyketones are described by using environmental friendly procedures. The butenolides esters and nitriles are obtained by cascade reactions of Dreux without solvent and under microwaves irradiation. The reaction was generalized with the synthesis of butenolides carrying a sulfenyle group, sulfoxide, sulfone and phosphoryl. By using BMIM, BF4 as ionic liquid, it is possible to make the synthesis with a good yield, while recycling the ionic liquid and the base. This reaction of Dreux was used for the domino synthesis of the alkaloid Cerpegine in a one-pot domino reaction. This domino synthesis allows the convergent and fast synthesis of a great number of analogues of Cerpegine. Finally a new synthesis without solvent and under microwaves irradiation of isobenzofuranones was discovered. This synthesis brings into play five successive cascade reactions starting from alpha hydroxyketone.
UNE METHODE SIMPLE, DOUCE ET EFFICACE DE DEPROTECTION DU N-Boc PAR Na2CO3
KOUBACHI J.(1)AND(2), EL KAZZOULI S.(1)AND(2), BERTEINA-RABOIN S.(1)*, MOUADDIB A.(2), GUILLAUMET G.(1)
We report here, the cleavage of N-Boc by treatment using Na2CO3 with the reflux of a mixture DME/H2O. This reaction is applied to various heterocyclic structures (azaindole, indazole, pyrazole, indolinone, quinolinone, oxazolone).
FONCTIONNALISATION «ONE POT» DES POSITIONS 3 ET 6 D’IMIDAZO[1,2-a]PYRIDINES SOUS IRRADIATION MICRO-ONDES
KOUBACHI J.(1)AND(2), EL KAZZOULI S.(1)AND(2), BERTEINA-RABOIN S.(1)*, MOUADDIB A.(2), GUILLAUMET G.(1)
The synthesis of imidazo[1,2-a]pyridines functionalized in positions 3 and 6 has been done in one-pot and under microwaves.
FABRICATION OF METALLIC NANOWIRES BY TWO-PHOTON ABSORPTION
TOSA NICOLETA(1)AND(2)*, BOSSON JOCELYNE(1)AND(3), VITRANT GUY(4), BALDECK PATRICE(1), STEPHAN OLIVIER(1)
A chemical system consisting of a metallic salt, a watersoluble polymeric matrix and an iron(III) citrate complex, acting as the photosensitive specie absorbing at two-photon, has been used to produce metal deposition upon exposure to a femtosecond laser. The fabrication of continuous and uniform gold nanowires has been optimized. Their dimensions vary from a few hundred nanometers to one micron for their widths, and range from a few to several hundred microns for their lengths.